Sir Philip Watts KCB FRS (30 May 1846 – 15 March 1926) was a British naval architect, famous for designing numerous Elswick cruisers and the revolutionary battleship HMS Dreadnought.

Watts was born in Deptford, Kent and educated at the Dockyard School in Portsmouth and the Royal School of Naval Architecture in South Kensington, London.

He held this post until 1912, when he was succeeded by Eustace Tennyson d'Eyncourt and became adviser to the Admiralty on naval construction.

In this capacity he played an important part when World War I came.

Being the designer of the first dreadnought battleship, it was now up to him to see the use that was made of the fleet which he had brought into being in previous years.